Only error about MSVC + PGO + unwind if we're generating code

When `rustc` is invoked with the `--print` argument, we don't actually
generate any code (unless it's the `native-static-libs` option). So we
don't need to error our in this case since there's no risk of generating
either LLVM assertions or corrupted binaries.

diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 3cbf0ee213ae371891821890de7a2086d3e61bc8..664926a152f14f03fb9b43ed1be157dc2dbbc58f 100644 (file)
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -9,7 +9,7 @@
 use crate::lint::builtin::BuiltinLintDiagnostics;
 use crate::middle::allocator::AllocatorKind;
 use crate::middle::dependency_format;
-use crate::session::config::{OutputType, SwitchWithOptPath};
+use crate::session::config::{OutputType, PrintRequest, SwitchWithOptPath};
 use crate::session::search_paths::{PathKind, SearchPath};
 use crate::util::nodemap::{FxHashMap, FxHashSet};
 use crate::util::common::{duration_to_secs_str, ErrorReported};
@@ -1306,9 +1306,12 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
     // an error to combine the two for now. It always runs into an assertions
     // if LLVM is built with assertions, but without assertions it sometimes
     // does not crash and will probably generate a corrupted binary.
+    // We should only display this error if we're actually going to run PGO.
+    // If we're just supposed to print out some data, don't show the error (#61002).
     if sess.opts.cg.profile_generate.enabled() &&
        sess.target.target.options.is_like_msvc &&
-       sess.panic_strategy() == PanicStrategy::Unwind {
+       sess.panic_strategy() == PanicStrategy::Unwind &&
+       sess.opts.prints.iter().all(|&p| p == PrintRequest::NativeStaticLibs) {
         sess.err("Profile-guided optimization does not yet work in conjunction \
                   with `-Cpanic=unwind` on Windows when targeting MSVC. \
                   See https://github.com/rust-lang/rust/issues/61002 for details.");